A basic system to provide efficient high speed ocean transport was disclosed in U.S. Pat. No. 3,274,966 issued Sep. 27, 1966, outlining a ship having a concave underside to generate a singular water wave from the forward motion of the ship, on which the ship rides above the rough ocean surface. At rest and at low speed this ship operates in a conventional displacement mode, where lift is provided by buoyancy forces. Speed in this mode is limited by wave drag due to water waves generated on the ocean surface. At high speed the concave bottom of the ship generates a singular water wave and rides on its crest in a dynamic lift mode referred to as surfing. In this mode the bulk of the ship is above the ocean surface with substantially reduced hull wetted area and surface friction, enabling cruise speeds in excess of 100 knots.
Transition between the low speed displacement mode and the high speed surfing mode requires additional provisions to generate sufficient dynamic lift at intermediate speeds to raise the ship from its displacement position, immersed in the water, to its cruise position on the crest of the surfing wave, and to provide stability and control to the ship when it rises above the ocean surface. Co-pending patent application Ser. No. 08/261,429 defines an invention providing for the transition requirements in practical operation of a surfing ship.
In ships with significant length and varying cargo loading requirements, stability and control of the surfing ship in both the transition mode and surfing mode may be limited by a single concavity and transition system located proximate the center of gravity. Enhanced capability for design and operation of surfing ships employing the invention with greater pitch stability and relaxed requirements for precise cargo loading is desired. These needs define the requirements for the present invention.